code: def format_html_styles():
      # type: () -> str
      """Format just the styles,
      use with ``format_as_html(explanation, include_styles=False)``.
      """
      return template_env.get_template("styles.html").render()
  
imports: from __future__ import absolute_import
  from itertools import groupby
  from typing import List, Optional, Tuple
  import numpy
  from jinja2 import Environment, PackageLoader
  from eli5 import _graphviz
  from eli5.base import Explanation, TargetExplanation, FeatureWeights, FeatureWeight
  from eli5.utils import max_or_0
  from .utils import format_signed, format_value, format_weight, has_any_values_for_weights, replace_spaces, should_highlight_spaces
  from .None import fields
  from .features import FormattedFeatureName
  from .trees import tree2text
  from .text_helpers import prepare_weighted_spans, PreparedWeightedSpans
label_desc: Use image node_id 2 for calling a global function with example usage: format_html_styles() and returns: template_env